Laser direct writing

Abstract

A method for providing a conductive metal deposit on the surface of a dielectric substrate by applying a composition comprising a mixture of a salt and amine or amide compound to the substrate and subjecting the composition to a continuous wavelength laser beam.

We claim: 
     
       1. A method for providing a conductive metal deposit on a substrate having a surface, the method comprising the steps of: a) applying a composition to said surface of said substrate as a film or paste wherein said composition comprises (i) a compound consisting essentially of a copper or nickel compound and,   (ii) an amine or amide compound having a nitrogen atom and at least one functional substituent group capable of coordination to and reduction of metal ions, said nitrogen atom and said functional substituent being separated by from two to six other atoms, or   (iii) an intermediate reaction product of (i) and (ii); and     b) subjecting that part of the applied composition where the deposit on the surface of the substrate is desired to a continuous wavelength laser beam of a wavelength from about 200 to about 1,000 nanometers and power of from about 5 to about 150 milliwatts at ambient conditions not employing an inert or reducing atmosphere and for a sufficient time to effect reductive deposition of copper or nickel, said film being thin enough or said paste being dispersed finely enough to allow unobstructed passage of said laser beam for absorption by the composition.   
     
     
       2. The method of claim 1, wherein said amine or amide compound further has at least one alkyl, alkenyl or acyl group of from 8 to 20 carbon atoms. 
     
     
       3. The method of claim 1, wherein said functional substituent is selected from the group consisting of hydroxy, amino, and carbonyl containing substituents. 
     
     
       4. The method of claim 1, wherein said at least one group carrying a functional substituent is selected from the group consisting of hydroxyalkyl and aminoalkyl. 
     
     
       5. The method of claim 1, wherein said amine or amide compound is hydroxylated. 
     
     
       6. The method of claim 1, wherein said amine or amide compound is selected from the group consisting of N-9-octadecanyl-1,3-propane diamine, n,n-bis-(2-hydroxyethyl) lauramide, and bis-2(hydroxyethyl) tallow amine. 
     
     
       7. The method of claim 1, wherein said substrate comprises a semi-conductor or a dielectric substrate selected from the group consisting of ceramics and polymers. 
     
     
       8. The method of claim 1, wherein said substrate comprises a dielectric substrate selected from the group consisting of glass, alumina, polyimide film and silicon wafer. 
     
     
       9. The method of claim 1, wherein said composition further comprises water or a liquid organic vehicle. 
     
     
       10. The method of claim 9, wherein the liquid organic vehicle is a mono- or polyhydroxy compound. 
     
     
       11. The method of claim 10, wherein the mono-or polyhydroxy compound is methanol, ethanol, isopropanol, glycerol, ethylene glycol, and polyethylene glycols. 
     
     
       12. The method of claim 1, wherein said laser beam is applied to said composition so as to produce conductive patterns of deposited metal having resolution in the area of one micron. 
     
     
       13. The method of claim 12, wherein said conductive patterns comprise lines of metal of said substrate of about 1 to about 20 microns width and about 3 to about 50 microns spacing between lines. 
     
     
       14. The method of claim 1, wherein said substrate comprises a printed circuit having patterns of conducting metal in need of repair because of cracks occurring in one or more portions of said patterns, said cracks being repaired by applying said laser beam to said composition in a manner that produces deposits of metal that bridge said cracks.